Speaking of Serpents
by herebesherlocks
Summary: They say that The Boy Who Lived has power the Dark Lord knows not. Problem is, Sherlock doesn't know what that power is, or how to use it. As usual, Mycroft isn't helping.
1. Chapter 1

Ignored by the hurrying throngs of people, a scrawny, black-haired boy stood before the glass case that housed the largest exhibit and stared inside. If any had stopped to notice the boy, they would have thought his unblinking gaze more suited to the snake inside—but the reptile was asleep, head resting on its coiled body, apparently unmoved by the carrying voices and occasional taps on the glass from the zoo's visitors.

Sherlock could definitely relate. Casting a quick glance behind him, he wondered what the rush was, why people scurried through a trip undertaken for pleasure.

Sherlock had never been to a zoo before, and didn't expect to be again. That was for people like Mycroft, who had pocket money and friends and, above all, a family who actually cared. So in spite of the stifling crowds, he was doing his best to enjoy it now.

Uncle Vernon was a gorilla, he had decided—loud and brash and prone to displays of aggression unless he got his way. Aunt Petunia was as graceless and bony as a giraffe, but carried herself through her unbearably dull life with all the self-satisfaction of one of the peacocks strutting between picnic tables with the pigeons. Mycroft was a panther, secretive and aloof. On certain occasions twining into your path like a housecat wanting attention. And always, always dangerous.

I am a snake, Sherlock decided, watching the inert, curled body in front of him. The serpent evidently thought so too, because all of a sudden its eyes snapped open, fixed on him. Sherlock caught his breath. For a moment, the noises behind him grew quiet.

He raised a hand to the glass, resting on its smooth surface, imagining that he could step through the glass to stroke the metallic scales and peer back more closely into the slitted pupils now boring into his.

"Hello," he murmured.

The snake arched its neck slowly upward until its head hung at his eye level. It stayed that way for a long moment, and then opened its fanged mouth, tongue flickering in and out. What came out didn't sound like a hiss.

"Hello, small human," it said.

Sherlock blinked very hard. He knew what Mycroft would say, what his teachers would say—this was impossible. Well, it was the latest in a series of things should have been impossible but weren't. Therefore it was logical to assume that some of the prevailing scientific theories were wrong, and proceed by gathering all the data possible.

"I didn't know snakes could speak," he said as casually as he could, ignoring the thudding of his heart against his ribcage.

"All creatures can sspeak," the boa constrictor replied, and this time Sherlock could hear the hissing undertone in its voice. "Excccept those that are incredibly dull." The serpent flicked its head lightly to the side, indicating the rushing crowd, one or two of whom were beginning to take notice of the reptile's strange behavior.

Sherlock grinned. "Most creatures, then."

The dip of the snake's head seemed to indicate affirmation. "Mosst creaturesss here."

"Where would you go, if you were free?"

The tail jabbed toward the glass, indicating a sign in the lower corner.

_Boa constrictor, native to Brazil. Bred in captivity, _Sherlock read. He glanced back up with a sympathetic grimace. "That's me, too."

He had no time to hear the snake's hissing warning when another voice sounded above his head, piercing in its mild eloquence.

"How very melodramatic of you, cousin." Mycroft was amused. "What have we here?"

Sherlock clenched his jaw. It wasn't like him to fail to notice Mycroft's approach, but it wasn't every day he got to talk to a snake, and despite his determination to act logically and solely for the sake of gathering data, he'd been carried away in the sheer delightful unbelievability of it all. He turned to his cousin with a carefully schooled expression of boredom.

"It's a boa constrictor, Mycroft. I was led to assume that your early graduation to secondary school was a good indication you could read, but apparently I was wrong."

"And you've been having a lovely little chat with it."

Sherlock clenched a fist, the one hidden from Mycroft's view—it wouldn't do to let his cousin know how close he had come to the mark. Though who knew how long he had been standing there?

"It seemed the only opportunity for intelligent conversation that would arise for a while." He turned back to the glass. The snake was resting its head again, but wasn't asleep. It seemed to be regarding him with almost an air of amusement.

"What?" Sherlock hissed.

"Do uss both a favor, small human."

"What do you mean?"

The tail tapped the glass again.

Sherlock brought his hand up to the smooth surface again; this time calculating. What the snake was suggesting was utterly ridiculous. Just like the time his teacher's wig turned blue, and the spontaneous combustion of Aunt Petunia's rhododendrons. But it wasn't as though he could actually…

Suddenly his hand was touching empty air. The glass had vanished.

Sherlock would treasure the look on his cousin's face for the rest of his life. Mycroft, usually calm, collected, and more pompous that any thirteen year old had a right to be, had seen the glass vanish and was stumbling backward in panic. The snake was moving within seconds—Sherlock felt a thrill as the huge serpent slithered toward him, past him…he could swear he heard a quiet "Thankss, amigo" as it went by…and then, with a playful nip at Mycroft's ankles, it was gone. In blind panic, Mycroft seized an umbrella from a passerby and brandished it at the snake, but it was already vanishing into the crowd. Sherlock pressed his back against a wall and smiled as the first few screams rent the air.

It wasn't very long before the letters came, in floods.

Sherlock had had barely a day to kick himself over letting that envelope into the presence of his aunt and uncle—_stupid, they never let you have anything, why would they let you have that?—_before the downpour came. It was one of the best—that is, least boring—afternoons of Sherlock's life. As Aunt Petunia and Uncle Dursley shooed him and Mycroft frantically out of the parlor, Sherlock could barely keep from rolling his eyes. He himself had three letters shoved down his shirt and another in the waistband of his too-large jeans; no doubt Mycroft had at least five.

No sooner had the brief, but very enlightening conversation between his parents ended before Mycroft corralled his smaller cousin into his room.

"All right," he said, steering Sherlock onto the rug and plopping down beside him. "Spill. I have little doubt that the contents of these letters are identical, but we may as well be sure." He removed a half-dozen letters from the sleeve of his cardigan as he spoke.

Sherlock scowled, but Mycroft's idea made sense, and since there was no way to prevent his cousin from reading _his_ letter he supposed they may as well pool their data. He pulled out the three letters he'd tucked away, leaving the one in his waistband hidden. Mycroft was unpredictable, and if he tried to hold on to the letters Sherlock wanted at least one copy to peruse at his leisure.

Mycroft seized a letter opener from his desk and carefully went about slitting the seal of the first envelope. Sherlock would have kept back at least one letter, of course; but that didn't concern him. What concerned Mycroft were the contents, and as he pulled a sheaf of oddly heavy paper (parchment, perhaps?) from the envelope Sherlock leaned forward and the two boys read together.

_Dear Mr. Potter,_

_We are pleased to inform you that you have been accepted at Hogwarts School of Witchcraft and Wizardry…_

When they had finished the letter—the beautiful, impossible letter—they set about opening the rest of the envelopes. Each letter was identical, down to the impossibly symmetrical curves of the handwriting. Sherlock turned the parchment over and over in his hands, studying it from every angle. Mycroft leaned back against the mattress, thinking.

"Whoever these people are, they're either pulling some massive practical joke on you—"

Sherlock's eyes cut his way for a split second, and Mycroft laughed.

"Far be it from me to waste this kind of resources on you, little cousin. Quite apart from the fact that I don't have two dozen trained owls at my command."

Even that wouldn't really surprise him, Sherlock thought, but knew better than to say it out loud. He settled for, "So either it's a joke, or this…magical society…has kept their secret from the whole world for years. Centuries, probably."

"I don't imagine it's all that difficult."

Sherlock shot him an incredulous look. Mycroft waved a hand lazily. "Trained owls and magical schools aside—I mean, if this _is_ real they'll have some sort of magical methods to cover that up anyway—but even if a few people notice, so what? They get labeled as drunkards or lunatics. Anyway, you heard Mother and Father. _They_ knew and kept it secret, and you'll never meet two such…"

"...boring…"

"…practical people," he finished.

Sherlock cast him that flat glance again, which Mycroft knew was an attempt to hide building excitement. "So _you_ believe all of this is true?"

"Scientific method, little cousin." He narrowed his eyes. "Don't think I've forgotten the vanishing glass incident," suppressing a shudder. "Don't tell me you had nothing to do with that. There is definitely something…"

"…special…"

"…weird about you."

Sherlock huffed. "You have only circumstantial evidence as far as the snake is concerned."

"Just like all the incidents at school."

This time Sherlock kept sullenly silent. It was really no surprise that Mycroft knew.

"All right." He threw a piece of parchment down in Mycroft's lap. "What do you make of it, I know you're dying to say…"

Mycroft needed no further encouragement.

"Emerald ink, not your standard ballpoint tip. Not a calligraphy pen either, but similar…I'd say a quill, except there's no variation in ink flow…no sign of dipping the tip to refill the calamus…"

Sherlock, lost in contemplation, opened his eyes long enough to give Mycroft a look that said _magic_.

Mycroft cleared his throat and continued, picking up an envelope this time.

"They've got your address here, down to your bedroom, which implies a highly efficient level of surveillance, to the point of creepiness…"

Sherlock snorted quietly. The irony was not lost on Mycroft.

"And the intricate wax seal, the coat of arms—"

"—indicates a near-obsessive fixation with tradition, as does the use of parchment instead of paper. However magical the society, I find it difficult to believe that it's more efficient to produce goat skins than wood pulp."

"Quite." Mycroft drew up his knees and regarded his younger cousin expectantly. "What are you going to do?"

"Because we've enjoyed such a close relationship all these years. Is there any particular reason I should begin sharing my thoughts with you?"

"Allies, little cousin. You saw how Mum and Dad acted, do you honestly want me on their side instead of yours?"

"Ah, the lovely yet treacherous bloom of family loyalty."

Unlike Sherlock, Mycroft made a point never to indulge in activities as uncouth as snorting, but he was sorely tempted now.

"Look at the resources these people have, do you think you could stay away from them if you tried? Mummy and Dad, much as I love them, are being delusional."

"I'm flattered," said Sherlock drily.

"You're _wanted,_ little cousin. Savor the unfamiliar sensation."

"Shut up," said Sherlock absently, scanning the parchment again. "You just want a…" he found it a little difficult to get the word out. "A _wizard_ on your side. Whatever side that may be."

After a minute he looked up, relenting. "I suppose I'll answer the letter. 'We await your owl'…that's obvious, at least. Nice of them to assume we all have intelligent predatory birds as pets."

"Who knows, you might have a talent for necromancy. Those remains in your room…"

Sherlock cut him off. "Were already dead, it's an _experiment_."

Mycroft walked to the window to regard the masses of fowls perched outside. "I think you're covered on that count anyway. Take your pick."

Sherlock, still sprawled on the floor, held up a hand in mock resignation. "Got a pen?"

Watching his cousin secure the folded notebook paper to the leg of an unnaturally tame chocolate-brown owl, Mycroft spoke up. "These letters are quite formal. You don't think it would be better to respond in kind?"

"What, and slaughter a goat?" Sherlock cast him a look of disdain. "Just because these people are stuck in the Dark Ages doesn't mean _I'm_ going to be."

Mycroft swallowed his grin along with an unexpected pang of jealousy. These wizards weren't going to know what hit them.


	2. Chapter 2

**A/N: Sorry about the wait, guys. Enjoy :)**

Sherlock stood back and took careful note of the pattern that Hagrid was tapping into the brick wall with the tip of his umbrella. Twenty minutes earlier, they had entered a sleazy little pub (the most unlikely-looking entrance to a grand magical world imaginable, if the words "Leaky Cauldron" had not been painted in faded letters on a creaky wooden sign.) The whole place looked as though it ought to be condemned, though probably they were going for 'unobtrusive'. It had not escaped Sherlock how the gazes of Londoners slid over the building as though it did not exist. But if the pub was enchanted so Muggles couldn't see it, why bother with unobtrusive? Unless the charm was simply a distractor? It made sense, after all; traditional magicians' tricks relied on distractions. Imagine what could be accomplished with _real_ magic, with the power to alter the mind's perceptions…

Sherlock watched in fascination as the bricks in front of him began to move. Vibrating, wriggling and twisting, they gradually opened a hole that grew wider and wider until it was a grand archway.

_Interesting model for molecular motion,_ thought Sherlock. He jumped when a large hand clapped down on his back, and looked up to see the groundskeeper grinning down at him.

"All righ', Sherlock? 'S a bit o' surprise, first time. Welcome ter Diagon Alley!"

They boy had been silent all morning, taking everything in with those brilliant green eyes. Hagrid eyed him worriedly. As a boy, James Potter was overconfident, arrogant even, and never at a loss for words. Lily, while more thoughtful, was equally intelligent—and didn't mind showing it. Neither had ever displayed much reserve, and though Hagrid had only known the boy for a day, it seemed out of character for their son as well.

* * *

The day previous, the groundskeeper had been escorted inside number four Privet Drive by a highly infuriated Vernon Dursley, who seemed to find Hagrid's bulk an affront to nature. Petunia Dursley had nearly fainted at the shock of seeing him, and he had been left standing on the front stoop for several minutes before a calm voice inside pointed out that the neighbors would surely start wondering what the giant of a man was doing on their doorstep. Sidestepping Dursley's bristling frame and squeezing into the narrow entrance hall, Hagrid had come face-to-face with the owner of the voice: a tall, slightly plump brunette boy, whose gaze fixed with amusement on the frilly pink umbrella Hagrid carried.

Hagrid had shifted his umbrella awkwardly into his other hand and wondered what to say—surely _this_ wasn't James' and Lily's son?—but before he could open his mouth, a younger boy, with a shock of dark curly hair, was skidding into the hall.

"Hogwarts?" he said, giving Hagrid a searching look with unsettlingly familiar green eyes.

"Yes, obviously," he answered his own question. "Took you less than a day to get here…I suppose you probably have magical means of transportation, but the owl that took my letter appeared ordinary, in terms of flying ability at least. So, judging by your arrival time, I'd assume that the school is somewhere in Britain, probably somewhere remote…Scotland?" he guessed, narrowing his eyes at the muddy stains on Hagrid's enormous boots.

"I imagine that your appearance isn't typical of wizards," he mused, "especially not if you're claiming I'm—Oh!" The boy's eyes lit up. "Do giants exist?"

Hagrid was spared answering by a muffled groan. He moved aside hastily, releasing the Dursleys, whom he had unintentionally pinned to the wall upon turning to meet Sherlock. A muffled voice he now recognized as belonging to the Dursley boy came from somewhere next to his elbow.

"I think this conversation should be continued in the sitting room, don't you?"

Sherlock led the way into the large room; at least, he had thought it large before seeing Hagrid in it. The giant man ducked his head, sending the light fixture swinging violently. He cast a helpless glance at Aunt Petunia's dainty cushioned chairs before taking up the entire width of the sofa. Aunt Petunia, now timidly peering over the shoulder of a livid Uncle Vernon, cringed as it sunk with an ominous groan.

Sherlock had taken a chair opposite Hagrid, grinning broadly. He seemed to have forgotten the others—the ungrateful brat, thought Uncle Vernon, swelling in outrage. Aunt Petunia looked on in fear as Mycroft calmly seated himself next to the fireplace.

"Rubeus Hagrid," said the giant, extending an enormous hand. Sherlock shook it, wincing as his own fingers were crushed in a fist larger than his entire head. "Keeper o' the keys and grounds a' Hogwarts."

"I'm Sherlock," the boy said quickly, pushing down the dozen or so fresh questions that sprang into his mind at these words. "Sherlock Potter."

The giant smiled for the first time, which had the effect of making his eyes almost disappear in the bushy beard covering his face.

"I know who yeh are," he said gruffly. "Knowed it as soon as I set eyes on yeh. Yer the spittin' image of yer da', Sherlock, wid' yer mum's eyes…though I 'spect them cheekbones came from Lily too."

In the doorway, Aunt Petunia let out a muffled squeak. Sherlock's immediate questions—about Hogwarts, and wizard transportation, and the potency of an individual's magic—died away on his lips. He had never heard his parents mentioned by name; it was always "your sister", and "that good-for-nothing" on the rare occasions they were mentioned at all. He leaned forward, gripping the arms of his chair tightly; suddenly—for no logical reason—needing desperately to know.

"What was my father's name?"

"James," said Hagrid, looking bewildered. "Yer father's name was James, o' course, don' ye know that?"

_Lily and James,_ Sherlock said to himself, tasting the names. _Lily and James…my parents…I had parents once…_

Of course he'd had parents, but they'd vanished so early, so completely, from his life; leaving (until now) nothing for him to remember them by, unless you counted the jarring nightmares that still woke him some nights. He'd been far too young to retain any memory of his parents, Sherlock knew, and the dreams he'd had for as long as he could remember were no doubt the products of his own brain, trying to fill in details of the car crash…though he had no idea where his subconscious had dredged up the green light from; copper residue in the flames could cause that, but it seemed highly unlikely…

"Blimey, ye've grown, Sherlock. I was the one that brung ya' here," Hagrid broke into his thoughts. His eyes filled with tears. "Just a tiny thing, you was, wavin' them fists and squallin'…I pulled ye' from the house just 'fore the Muggles showed up."

"House?" echoed Sherlock distractedly. "Do you mean car?"

Now Hagrid looked stupefied. "Car? Wha' car?"

"The car crash that killed my parents," Sherlock said impatiently. "Were you there? Did they crash into a house?"

Before Hagrid's outrage had time to manifest itself on his face, Sherlock knew.

He didn't remember getting to his feet. "They lied."

Sherlock took a trembling step toward his uncle, fighting down his rage. Vernon was planted in the doorway looking mustache bristling defiantly, and looked not the least bit sorry. "DIDN'T YOU?"

"And what if we did?" his uncle snarled back, wearing a very ugly expression indeed. "Took you in, didn't we? Didn't have much bloody choice…I swore when they dumped you on our doorstep we'd stamp the unnaturalness out of you, but now I see what I should've known since day one, there wasn't a chance of you turning out decent…"

"DECENT?" roared Hagrid, who was suddenly on his feet and seemed to fill the whole room. "And ye call this decent, do yeh, Dursley? Dressin' him in rags…doesn' know 'is own parents' names…"

"Take him then!" shrieked Aunt Petunia, who had grown so pale she was in danger of blending into the wall. "Take him to this, this _magic_ school of yours, let him turn out like my freak of a sister, just don't come crawling back to tell us when he gets himself blown up too…"

"Blown up?" whispered Sherlock, who had taken another faltering step toward his aunt. Something very strange was happening in his mind, as though her words had unlocked a door and a rush of memories was pouring out. These weren't memories, though, they couldn't be; they were _dreams_, and he felt a swooping rush of nausea as the emerald light flared brighter than ever behind his eyelids, and this time his mother's screaming was accompanied by high, cold laughter…

He was vaguely aware of more raised voices, and tension building to a dull pounding in his head—and then pain ripped across his scar, an explosion shook the room. Dazed, Sherlock felt himself grabbed and dragged backwards…the echo that sounded in his ears was nearby and far off all at once…and then there was silence. Uncle Vernon and Aunt Petunia were standing, frozen and slack-jawed, staring at Hagrid. Sherlock felt himself released from behind; the explosion had jolted him back to his senses. The room didn't appear to be destroyed, although there were scorch marks on the walls and ceiling, and most of the furniture had toppled and was lying at various odd angles. Looking up, Sherlock saw that the light fixture was still intact, though swaying violently above the spot where he had been standing. Bits of plaster dotted the cream-colored carpet. It was as though a very small, concentrated lightning storm had ripped through the room and then left.

Mycroft's voice sounded behind Sherlock, almost as jarring in the shocked silence as the raised voices had been.

"Perhaps we ought to carry on this conversation without further upsetting the delicate internal balance of my cousin."

* * *

Vernon and Petunia Dursley had left the room following the explosions, Uncle Vernon quite purple in the face, still grinding his jaw and muttering under his breath about "magic tricks" and "Better not come crawling back here after that show". Neither of them, however, seemed keen to confront Hagrid anymore; it was clear they both thought that the sooner they rid themselves of their nephew, the better. Mycroft stayed behind, the lone spectator, and Sherlock impatiently bit back his most urgent questions, the ones about his mother and father and how they'd gotten themselves "blown up".

Hagrid explained about Hogwarts, Diagon Alley, and Sherlock's school supplies; blissfully unaware that both cousins were doing their best not to cringe at his grammar. When the explanation wound down, Sherlock made an unexpected request.

"Do some magic," he said.

Hagrid was taken aback. "Do some…blimey, Sherlock, don' yeh believe me, after wha' yeh just did?"

Sherlock schooled his expression carefully.

"What I felt," he said, "was an explosion. Explosions can have any number of possible causes. That I was the catalyst of this one seems probable, but thus far you have offered me no evidence that Hogwarts school even exists."

"Or that magic can be controlled," put in Mycroft, amused.

Sherlock glared at him.

"Why are you still here?"

"My mum's living room?"

"I never knew you were so fond of it."

"You're blocking the telly," said Mycroft.

Sherlock determined to do what he did best, and ignore him.

Hagrid's hopes that the request for magic had been forgotten were dashed when Sherlock turned back to him expectantly.

"Er…" he twisted the frilly pink umbrella in his thick fingers, avoiding Sherlock's eye. "It's just that, strictly speakin', I'm not supposed ter do magic…"

Mycroft interrupted smoothly. "Surely it would be permissible here. After all, you were sent to explain the magical world to a boy who has grown up without magic. There's no telling how difficult he'll be to convince."

Sherlock joined in, looking skeptical. "I'm sorry, Hagrid. I really am. But you have to admit it sounds pretty unbelievable."

He stood, dusting bits of plaster off his jeans, and offered his hand to the flustered groundskeeper. "Thank you for your time, sir, I'll show you out."

To Mycroft's everlasting credit, he kept a completely straight face.

* * *

"I must say, cousin, I'll miss the melodrama when you're gone."

"Ah oo ike atchyer ads ood eshur ise."

"What?"

Sherlock rinsed and spat into the bathroom sink. "I said, I too enjoy watching your dad's blood pressure rise."

"Charming."

Sherlock grinned. "You never know. With me gone, he could fall below, oh, 180/120."

"I suppose tomorrow, as soon as I'm not around, you'll ask Hagrid about _your_ parents?"

The grin vanished. "Obviously."

"Diagon Alley sounds quite…enchanting. Try not to get too distracted by shiny objects." Mycroft's voice dropped for a moment. "I would like to know, as well. If you don't mind telling me."

He sounded a little too sincere. Sherlock narrowed his eyes.

"Why would you care?"

"Lily was my aunt, you know."

"Oh, are we saying their names now? I thought that was taboo." Sherlock didn't bother to hide the bitterness in his tone.

Mycroft squeezed an impossibly even amount of toothpaste onto his own toothbrush.

"I don't actually think you or your parents are the root of all evil, you know. Or magic either," he added thoughtfully.

"Don't you?" Sherlock sounded genuinely surprised. There was silence for a moment, that hovered halfway between awkward and comfortable.

Then Sherlock, with characteristic mercuriality, spat the words at his cousin. "Did you know?"

"No, Sherlock. I promise."

Sherlock knew very well that Mycroft's promises were worth exactly the measure of inconvenience it would cause him to break them.

"Lies have tells," he growled, believing him anyway. "Uncle Vernon's rubbish at hiding them…I should have known—you _definitely_ should have known…"

"You were perhaps four when you asked the question," Mycroft replied smoothly through a mouthful of toothpaste. (Sherlock would've given his stolen chemistry textbook to know how he managed that.) "I was six. And I was most likely at school."

"You remember."

"I recall the dust-up at dinner that evening on the subject of flying motorcycles," returned Mycroft drily. "It tends to stick in the memory."

* * *

"Is there anything else you'll miss?"

Sherlock's voice drifted from the bedroom at the end of the hall, to which he'd reluctantly been permitted to relocate several years before, after a "minor" chemical fire in his cupboard had nearly trapped the entire Dursley family on the second floor. Of course he'd paid for it, living off bread and water for nearly a month—but it had been worth it.

Mycroft, clad in long silk pajamas, was just carrying a carefully made cup of tea up the stairs. Sherlock lounged against the door frame, more elegantly blasé than any eleven-year-old in hand-me-down pajamas had a right to look.

"Besides the drama. I wondered if you'd miss the charm of my company."

It was a suspiciously casual question. But Mycroft knew it _was_ casual; Sherlock himself didn't care for anyone's company, least of all his cousin's, and there was no love lost between them. Mycroft sometimes doubted whether Sherlock would have understood the concept of familial affection even if he had grown up in a less dysfunctional family.

"I might miss Fluffy." Mycroft nodded at the salmon-pink cushion that represented Hagrid's eventual concession to performing magic; he'd been attempting to turn the thing into a cat, and it was now sporting pointed ears but remained stubbornly rectangular, if a bit fluffier.

Fluffy mewed. Sherlock stroked its ears.

"Fluffy will miss you too," he drawled.

And that was all there was to be said.

**A/N: Let me know what you think! I love reviews, and I keep your comments in mind. What do you think of the dynamic between Sherlock and Mycroft? Of course they're cousins instead of brothers here, and a lot younger-and also, Sherlock has a lot more cause for resentment. But I kept it quite similar to the show. (And sorry, I'll throw in some interaction between Mycroft and his parents, soon. That definitely needs clarifying.)**

**Also, I apologize for not getting to Diagon Alley this chapter. I have plans for next chapter :) Also, sorry Sherlock Potter doesn't have quite the same ring as Sherlock Holmes...I thought about changing it...and then I was like, naahh...**

**Until next time, Holmies. **


	3. Chapter 3

Hagrid's worry vanished the moment the pair set foot in Diagon Alley. Sherlock flitted about from one shop to the next, enthralled. Every few feet he stopped, transfixed by a jar of exploding ink or a cauldron advertised for special brewing capabilities, and utterly deaf to Hagrid's importunities to move on. Hagrid simply didn't understand; it wasn't the objects themselves that captivated Sherlock, despite their intrinsic lure. It was the _possibilities_. The variety and balance of spells powering these objects…Sherlock couldn't even imagine, didn't have the _data_. That, he vowed, would change, and soon.

He was examining a crystalline light refraction device in a shop window (ignoring an intricate, slowly revolving model of the solar system) when at last the groundskeeper seized him by the arm and dragged him away so they could visit Gringotts. Sherlock offered no resistance, although his barrage of questions (Does Transfiguration work on any substance? Were those real unicorn horns? How do you make a spell permanent? Does the lift generated by a broomstick depend solely on the strength of the charm?) didn't stop until they were passing through the double doors at the top of the bank's marble steps.

At his first sight of a goblin, Sherlock fell abruptly into the same silence that had alarmed Hagrid as they left the Leaky Cauldron…though he had traded his pensive mood for seething excitement. Here were nonhuman creatures of real intelligence. Considerably more intelligent, in fact, than most of the humans he had known (hardly a feat, but interesting nonetheless). Actually, the question of their evolved intelligence (divergent or convergent with humanity?) and their involvement in wizard finances (how easily this arrangement could transform into the sort of power play Mycroft relished) intrigued him far less than the thrilling, breakneck ride through the caverns. And even that excitement paled beside the mystery of the grubby little parcel that Hagrid had just tucked into a pocket of his overcoat.

"What is it?" Sherlock queried instantly, when they stepped into sunlight again. The fat bag of gold from his own vault may as well have been an afterthought.

"Can' tell yeh that," said Hagrid mysteriously, patting the bulge in his coat. "Top secre' assignmen' from Dumbledore."

Sherlock wrinkled his nose. Hagrid didn't exactly seem the type to whom one entrusted confidential and probably valuable, powerfully magical items for long periods of time. (The irony of this quite flew over his head as he trotted next to Hagrid's side; certainly no one had ever attributed any value to _him_). Hagrid's management of the package was obviously temporary. It would almost certainly return to Hogwarts and its headmaster as soon as possible. What an odd name, thought Sherlock, choosing to overlook this bit of irony also.

The really frustrating thing was that he could deduce nothing from his brief glimpse of the package itself, simply because he knew nothing of the world to which it belonged. Grubby, unobtrusive, the Leaky Cauldron all over again…and again Sherlock wondered, why bother? In this world oddities were overlooked as a matter of course; a witch hurrying by in violently magenta robes garnered far fewer stares than Uncle Vernon's business suit and neatly trimmed mustache would have done.

He was simply missing too many pieces. _Data, I need data._

If Hagrid's hurried suggestion that they go shop for potions ingredients was meant partially as a distraction, it worked to magnificent effect.

* * *

Half an hour later, Hagrid dragged Sherlock away from a very browbeaten apothecary (who was starting to rethink his profession, as he didn't really know or care _why_ lionfish quills were so effective in paralyzing draughts, and was even less eager to know what an eleven-year-old wanted with them).

Sherlock and Hagrid left the shop with, as the latter patiently explained to his charge, at least twice the variety of ingredients he could possibly need for a first-year Potions class. Sherlock waved this off.

"I can hardly experiment with inadequate materials," he said. "Besides, I've thought of some variations on the combustions tests I was running last semester in the chemistry lab. Convention will only slow me down."

The experiment had been going so smoothly too, he thought sourly. Until the little snag that precipitated a totally unnecessary call to the fire department. Despite what Mycroft thought, not all of Sherlock's 'incidents' had anything to do with magic.

The trip to Flourish and Blotts resulted in much of the same.

"Blimey, Sherlock," Hagrid groaned from beneath a stack of the thick, finely-printed books that found their way into the nightmares for any NEWT-bound student. "I don' see 'ow any of this will fit in your trunk."

"Indetectable Extension Charm," Sherlock informed him, flipping through an embossed, leather-bound volume. "I looked it up before we left the shop. There's a footnote here on weight reduction, as well…It might take me a couple of days to work it out, but I suppose I have plenty of…" his voice trailed off.

They were standing in front of the most fascinating shop yet. Sherlock didn't need the words "Magical Menagerie" plastered above the door to tell him what it was; the growls, squeaks, and hoots crowding out of the doorway told their own story.

"Er," said Hagrid roughly, shifting from foot to foot. "S'a bit earlier than I planned, but I wanted ter get yeh a bit o' a late birthday presen' …I was thinkin' an owl, they're dead useful. Thought we might try Eyelops…"

But the boy, eyes shining, had already disappeared inside the shop. Hagrid followed, stooping low under the doorframe and squinting in the half-darkness.

"Good afternoon," said a voice next to his elbow, making him jump. A pinched-looking wizard wearing electric-blue robes and sporting an oily black mustache beamed up at him with the certainty of one who has exactly what his customers are looking for, even if they don't know what that is.

Sherlock moved dreamlike through the tiny shop. He could hardly see the walls; cages and terrariums crammed into every possible space and hung from the ceiling. The animals inside were a fantastic cross between the ordinary and his wildest dreams: jeweled tortoises, softly hooting barn owls with metallic claws, a luminous ferret whose gaze followed him across the store.

He came to a stop in the back corner beside the last cage. The creature within was silent, watchful, large green eyes fixed on his in a way that was at once inviting and apocalyptic. Sherlock fell in love at once.

"Ah," came the oily voice of the shop owner, who had appeared silently at his side. "You like her?"

"Yes," Sherlock heard himself breathe, so quietly he wasn't sure the shopkeeper heard him. "What is she?"

The little wizard squinted past his pointed nose at the boy. This was not a question that most people asked regarding what, after all, appeared to be an ordinary cat. Then again, the boy didn't look like 'ordinary' was his specialty either.

"She's a cat, of course," he said after a pause. "Mostly. Got some kneazle blood, too—intelligent, them, and rare. There's not many would notice the difference."

Sherlock studied the tiny paws, the long fur that was glossy black but somehow _wild _and did a poor job of hiding the taut muscle underneath. The creature was incredibly graceful, even for a cat. The intelligent emerald eyes remained locked on Sherlock, and neither looked away as Hagrid fumbled his way to the back of the store, bent nearly double and letting out a stream of curses.

"She's beautiful, why is her cage shoved all the way back here?"

"Doesn't get along with most folks," the man chuckled. "Yowls loud enough to wake half the shop, sometimes…you're the first I've seen who she didn't take an instant dislike too."

"Locked in a cage, watching every idiot who walks by stick his fingers between the bars…I can hardly blame her," returned Sherlock drily.

Hagrid was in agreement. "There's few creatures yeh can't ge' along with, so long's yeh treat em right."

The shopkeeper nodded, the smile plastered beneath the moustache almost genuine. "I can let her go for six galleons."

Sherlock didn't even have to turn pleading eyes on Hagrid. Five minutes later, he was strolling out of the Magical Menagerie, a warm, furry bundle purring contentedly in his arms.

* * *

Another twenty minutes after that, the strange tingling rush of magic was running up his arm for the first time. The kneazle-cat twined round his legs in silent applause as red-and-gold sparks lit up the dusty corners of the little shop, and a man with irises like moonlight told a strange story.

* * *

Uncle Vernon was less than pleased.

"I don't recall offering refuge to any more strays," he snarled nastily; his hands twitched at his side, obviously itching to throttle his nephew.

The cat stopped on the landing and fixed him with her unwavering stare.

"Besides," added Aunt Petunia fitfully, with a nervous glance at her newest tenant. "Mycroft's allergic, aren't you, Mikey?"

Mycroft ground his teeth inaudibly.

"I think I can manage, mother. Just tell him to keep it locked in his room until term starts…or better yet, shut the thing outside," he added, as Sherlock shot daggers at him.

The cat gave him an approving stare and continued picking her way up the stairs, intent on inspecting Sherlock's quarters. Mycroft had no idea why his cousin had brought home a long-haired cat, of all things, if not to annoy him...Mum was right, his eyes were already watering…but it was fairly obvious that any attempts to get rid of it would end badly for all parties involved.

And more importantly, he had an alliance to forge.

* * *

"Acquired a familiar already? You're jumping in with both feet, aren't you?"

Sherlock was reading, and made no answer beyond lifting a smug hand to stroke the ears of the creature curled at the foot of his bed.

"I never knew you were so narcissistic," Mycroft continued.

"Yes, you did."

"It's quite remarkable, really…it's almost…" Mycroft's thoughts drifted off as he stared at the thing. It was so obviously a perfectly normal black cat. Except it wasn't.

"…almost a feline manifestation of yourself."

Sherlock actually glanced up at that, grinning. "Why Mycroft, how poetic of you."

"Not as poetic as the name you gave her," Mycroft pointed out.

Sherlock let the book drop to his chest. "It was fitting. Besides, Fluffy was already taken."

"Belinda," tried Mycroft slowly. "You know, I think I see it."

* * *

One month later, Sherlock was going mad with anticipation. His aunt and uncle felt much the same way, though for different reasons. Sherlock had spent half of the last month locked in his bedroom. Only Uncle Vernon's futile hopes that his new schoolbooks would distract Sherlock from "that blasted chemistry set", combined with the unsettling look in his nephew's eye, had prevented him from locking the boy's school supplies in the cupboard under the stairs. These hopes, however, proved unfounded when the explosions punctuating the night only increased in volume and frequency.

Uncle Vernon felt that the only way to handle this annoyance was to rid himself of another, namely the sight of his nephew's face. And so Sherlock had been forbidden to set foot outside his bedroom until leaving for Hogwarts.

Sherlock didn't mind this at all; the respite from Aunt Petunia's many chores left him with all the time he wanted to practice with his new wand and study his schoolbooks, occasionally scrawling improvements in the margins. He was flipping through a Charms book for a fireproofing spell (potion brewing, he'd discovered, was best not attempted on thick carpet) when Belinda raised her head and mewed loudly. Half a minute later, the door opened silently.

Suspiciously silently, thought Mycroft, edging through the doorway.

Sherlock looked up. Aside from Aunt Petunia's daily interruptions with food, it was the first time the door had been opened by anyone other than himself in several weeks.

"We're going," said Mycroft.

"Where?"

"You know where." Mycroft was wearing the dark vest and trousers with a long black jacket that Sherlock vaguely recognized as his new school uniform. He tried for a moment to remember where Mycroft was going. Somewhere boring.

"That's right. What's the school, again?"

"Eton."

Sherlock smiled evilly. "Eatin'. How…fitting."

"Juvenile."

"Speaking of fitting, it's a pity you never got to try on the Smeltings uniform."

Mycroft gave a long-suffering sigh. "Two weeks in solitary have done nothing to improve your manners."

"They've done nothing to soften your heart. What will Mummy do without her Mikey-Wikey?"

Mycroft's choice of secondary educational institution had brought on one of the very few altercations in the Dursley household that was not caused by Sherlock. Mycroft had won, in the end, by testing into a King's Scholarship at Eton College. That he had done so without the knowledge or consent of either of his parents in no way lessened the achievement.

"Dad says that if he comes back to find the house burned down or the walls smeared with frog intestines, you will never see the light of day again."

Sherlock brightened at this. "Then you're all going?"

His cousin winced. "It wasn't my idea."

"And staying overnight?"

"Obviously."

There was a pause during which Sherlock struggled to hide an evil grin from Mycroft, and was saved when Uncle Vernon stuck his head in the door to reiterate his threats. Sherlock smirked throughout the entire lecture.

"And you'll be getting to the station on your own, boy!" barked Uncle Vernon when he was through. "Don't even think of leaving that…creature…here." He returned Belinda's baleful glare.

"To your tender loving care? Wouldn't dream of it. I pity the poor, helpless creature who's left on your doorstep—oh, wait. Bad subject."

Mycroft watched his father's face flourish a deeper purple and reflected that Sherlock might have been spot on about the blood pressure. He also realized that he had missed his last opportunity to ask Sherlock about his parents before leaving for school…but unless the right moment presented itself, it would do no good anyway. He would see his cousin again in nine months. In the meantime, he had research to do. Not all of the academic variety.

Some of it Sherlock would be doing for him, although he didn't know it.

Mycroft lingered a moment longer as Vernon's heavy tread retreated. He didn't quite know why.

"_Can_ you get to London on your own? And find the platform?" He remembered the implausible platform number and wondered whether wizards studied higher mathematics. Heaven forbid they find out about imaginary numbers.

"I can handle it." Sherlock didn't sound worried.

"Well, then…see you. And your…pets."

Mycroft's eyes scanned the room, looking for the familiar salmon pink.

"Don't bother," Sherlock interjected. "You won't have to say goodbye to Fluffy after all."

"I—what?"

Sherlock was quite certain he was not imagining the dawning horror on Mycroft's face. He smiled sweetly.

"Belinda doesn't like it. I packed it for you."

Mycroft cursed inwardly, picturing the trunk buried beneath the small mountain of overnight bags and mum's hair supplies in the luggage compartment of the car. Suddenly the lingering guilt over the bugs he'd planted in Sherlock's own trunk vanished completely.

He closed his eyes. "Do you mean to say that a bright pink, mysteriously meowing…"

"Mike!" sounded Aunt Petunia's voice from downstairs. Mycroft and Sherlock winced in unison.

The former managed to contain his rage just enough to offer his cousin a goodbye smile. (Sincerity would have been too much to ask for.)

"Farewell, cousin."

"Laterz," replied Sherlock, flopped on his back and once again absorbed in his book.

"I was experimenting with reinforcing the animation charm," Mycroft heard his cousin remark absently as the door swung shut rather harder than intended. "It does more than meow, now…"

* * *

**A/N: So here's chapter three! I apologize profusely for the long wait. I recently got a job, and obviously that eats into most of my time. Anyway, hope you all enjoyed Diagon Alley. In case you are wondering, no I did not forget about Sherlock learning of his parents' fate. Also, I promise that this story isn't just about Sherlock and Mycroft...I simply love writing their conversations.  
Not all of the scenes from the books will be done in this level of detail, and though I will use it as a guide I am NOT planning to simply rehash the Harry Potter plotline. That would be boring, and we all know what happens when Sherlock gets bored. (the wall had it coming). **

**I chose Eton College for Mycroft (c'mon, did you really think he would go to Smeltings?) because it has an illustrious history and has been called "the chief nurse of England's statesmen". It is, dare I say it, rather fitting for Mycroft. (Disclaimer that I don't know a dang thing about the ages of students there or how the educational system in the UK differs from the US. Either way, Mycroft going to high school or even college at thirteen doesn't seem like much of a stretch. I wanted him older than Sherlock, but the canonical seven-year age difference would have been a bit much). **

**Interestingly, Wikipedia informs me that the 1985 movie ****_Young Sherlock Holmes_**** was filmed at Eton and written by Chris Columbus, director of the first two Harry Potter films. And young Sherlock's rival was apparently a student named Dudley...**


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